title: Molecular diversity in rice blast resistance gene Pi-ta makes it highly effective against dynamic population of Magnaporthe oryzae.
abstract: Rice blast is one of the important diseases of rice which can be effectively managed by the deployment of resistance genes. Pi-ta is one of the major blast resistant genes effective against pathogen populations in different parts of India. We analysed allelic variants of Pi-ta from 48 rice lines selected after phenotyping of 529 rice landraces across three eco-geographical blast hot spot regions. Besides, Pi-ta orthologue sequences of 220 rice accessions belonging to wild and cultivated species of rice were also included in the study for a better evo-devo perspective of the diversity present in the gene and the selection pressures acting on this locus. We obtained high nucleotide variations (SNPs and insertion-deletions) in the intronic region. We also identified 64 haplotypes based on nucleotide polymorphism in these alleles. Pi-ta orthologues of Indian landraces were scattered in eight major haplotypes indicating its heterogenous nature. We identified a total of 47 different Pi-ta protein variants on the basis of deduced amino acid residues amongst the orthologues. Five unique and novel Pi-ta variants were identified for the first time in rice landraces exhibiting different reaction types against the Magnaporthe oryzae population. A high value of Pi(non/syn) was observed only in the leucine-rich domain of the alleles cloned from Indian landraces, indicating strong selective forces acting on this region. The detailed molecular analysis of the Pi-ta orthologues provides insights to a high degree of inter- and intraspecific relationships amongst the Oryza species. We identified rice landraces possessing the effective alleles of this resistance gene which can be used in future blast resistance breeding programmes.
authors.affiliation: National Research Centre on Plant Biotechnology, IARI, Pusa Campus, New Delhi 110012, India.
authors.forename: S
authors.initials: S
authors.lastname: Thakur
authors.forename: Y K
authors.initials: YK
authors.lastname: Gupta
authors.forename: P K
authors.initials: PK
authors.lastname: Singh
authors.forename: R
authors.initials: R
authors.lastname: Rathour
authors.forename: M
authors.initials: M
authors.lastname: Variar
authors.forename: S K
authors.initials: SK
authors.lastname: Prashanthi
authors.forename: A K
authors.initials: AK
authors.lastname: Singh
authors.forename: U D
authors.initials: UD
authors.lastname: Singh
authors.forename: D
authors.initials: D
authors.lastname: Chand
authors.forename: J C
authors.initials: JC
authors.lastname: Rana
authors.forename: N K
authors.initials: NK
authors.lastname: Singh
authors.forename: T R
authors.initials: TR
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D060467:Disease Resistance / Q000235:genetics*; D005828:Genetics, Population; D006239:Haplotypes; D007113:Immunity, Innate / Q000235:genetics; D007194:India; D007438:Introns; D020082:Magnaporthe / Q000235:genetics / Q000472:pathogenicity*; D012275:Oryza; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: C413574:Pi-ta protein, Oryza sativa; D010940:Plant Proteins; D018160:Receptors, Cytoplasmic and Nuclear